March 03, 2007

AAPA 2007 abstracts

The 2007 meeting of the American Association of Physical Anthropologists will be held in about a month. As in previous years, here are some interesting abstracts to be presented at the meeting (pdf).

(up to page 94)

Homo floresiensis Cranial and Mandibular MorphologyJ.Y. Anderson, University of New MexicoThese results suggest the Flores material does not represent a population derived from Australomelanesians, and do not represent a non-pathological dwarfed population of Homo sapiens. These results do not completely rule out a representation of a microcephalic dwarfed population, at the same time it is suggested possible affinities to earlier hominin groups is equally parsimonious.

Do Qafzeh and Skhūl represent the ancestors of Upper Paleolithic modern humans? A dental perspective.S.E. Bailey et al.If these fossils represent the source of early Upper Paleolithic people, there is no need to invoke admixture with Neandertals to explain archaic dental features observed in some early Upper Paleolithic humans.

Reconstructing the settlement history of the central Andes from mitochondrial DNA analyses.K. Batai et al.We found that among central Andean ancient and modern population samples, haplogroup B frequencies increased through time, while haplogroup A frequencies declined. At this point, we do not yet have sufficient data to determine whether these patterns indicate different population histories between ancient coastal and modern highland populations, or a larger temporal trend in entire central Andes region

Analysis of Genetic Diversity in Ethnic Populations of AfghanistanP. Bermudez et al.The Middle East has the distinction of being a major crossroads of human migration. The genetic diversity of Afghanistan, however, has long remained a missing piece to this rich and complex puzzle. To explore both the diversity within Afghanistan and to understand the relative genetic contributions from various groups throughout the Eurasian continent, buccal swabs were collected from 252 unrelated Afghani men for mitochondrial DNA analysis. Each of these men hailed fromone of four major ethnic groups inhabiting the region: the Pashtun, Hazara, Tajik orNooristani. The Indo-Iranian speaking Pashtun represent the largest ethnic group in Afghanistan; the Tajiks have a complex genetic history that likely involves admixture between Turkic groups and smaller distinct ethnic groups within Afghanistan; the Hazara, on the other hand, are thought to represent remnants of Ghengis Khan’s army left behind as it expanded through Asia; and the Nooristani have biological links to populations in northern Pakistan and theclaim of descent from Alexander the Great’s army. All samples were analyzed for HVS1and SNP variation. In all of these populations, Western Eurasian haplogroups (H, HV, R, J, I, U, X) were most common, with the highest frequency occurring in the Nooristanis, while the remaining East Eurasian haplogroups including D, G, and various other M types. The results of this study will be instrumental in expanding our knowledge of Afghani genetic history, in addition to broadening our understanding of population migrations throughout West and Central Asia.

Dental variation in Holocene Khoesan populations.W. Black et al.

Are the Koh an indigenous population of the Hindu Kush? II: a dental morphology investigation.

S. Blaylock and B.E. Hemphill

Little is known about the population history of the ethnic groups in Chitral District, Pakistan, an area long been regarded as the “crossroads of Asia.” Some scholars emphasize that the Koh lifeway is the consequence of long-standing indigenous isolation. Others stress the equestriantradition among Koh villagers indicate they are descendants of Central Asians who emigrated across the Hindu Kush Mountains during the second millennium BC. To still others, an array of Persian linguistic inclusions indicates the Koh are more recent emigrants from the Iranian Plateau. This investigation tests these hypotheses for Koh origins through assessment of dentalmorphology variations of the permanent dentition scored as 17 tooth-trait combination in accordance with the Arizona State University Dental Morphology System in a sample of 134 Kho school children from Chitral City. These data were contrasted with 17 additional samples. Comparisons are in two stages and include cluster analysis, multidimensional scaling and principal coordinates analysis. First, sex-pooled and sex-specific data compared Koh to six contemporary ethnic groups from India. Results indicate the Koh share equidistant affinities to Indo-European speaking west-Central Indian and Dravidianspeaking South Indian ethnic groups.Second, sex-pooled data compared the Koh to 13 prehistoric samples from Neolithic to Early Iron Age sites located in the Indus Valley, Central Asia and the Iranian Plateau. Results indicate that the Koh share little affinity to prehistoric Indus Valley groups. Rather, the Koh share nearly equal affinities to prehistoric inhabitants of the Iranian Plateau and Central Asia.

A Howells grasp on prehistoric and recent Japan: A precursor to the Kennewick connection.C. L. Brace, N. Seguchi.Using many more samples, our results are compatible with what Howells showed for his Japanese comparisons, and,using the neighbor-joining technique, we can go on to show that Kennewick ties with the Ainu who are the descendants of the Jōmon.The Jōmon then are the probable ancestors ofthe first inhabitants of the western hemisphere.

Admixture in Mexico City: implications for admixture mapping.E. Cameron et al."The average proportions of Native American, European and West African admixture were estimated as 65%, 30% and 5% respectively."

"In a logistic model with higher educational status as dependent variable, the odds ratio for higher educational status associated with an increase from 0 to 1 in European admixture proportions was 9.4 (95% credible interval 3.8 – 22.6). This association of socioeconomic status with individual admixture proportion shows that genetic stratification in this population isparalleled, and possibly maintained, by socioeconomic stratification."

Social stratification in a Christian cemetery? An assessment of stress indicators and social status at Anglo-Saxon Raunds.E.F. Craig, J.L. Buckberry"The occurrence of statistically more individuals with both cribra orbitalia and tibial periostitis in plain graves rather than graves with stone arrangements, and LEH in plain graves rather than graves with a cover or marker, suggests that individuals buried in more elaborate graves enjoyed better levels of health and may been of higher social status than those buried in plain graves."

Variability of the Stature of the Central European Population from the Neolithic Age to PresentM. Dobisíková, S. Katina, P. VelemínskýThe aim of our contribution is to characterize the changes of the stature in adult populations that have lived in Central Europe from the Neolithic period up to the present. Our sample consisted of 802 male and 704 female skeletons. The evaluation was conducted taking into account the demographic structure of the groups studied. We confronted the findings with the livingconditions of the populations known to have a significant impact on human stature, inaddition to genetic factors. We thus considered the socioeconomic status of the populations that might have influenced the quality of nutrition. We focused our attention on the socioeconomic aspect of populations of the early Middle Ages and the recent population. We compared socially higher placed part of the society with socially poorer classes (agricultural groups) (177 male, 178 female) in the early-medieval population of Great Moravia. No statistically significantdifferences were found among individual social groups. To calculate the stature of last populations we used the regression equations developed by Breitiger (1937) and Bach (1965). Thecalculation was based only on the length of the femur that is directly involved in body length. The impact of the secular trend was evaluated in the recent population. We compared two autopsy skeletal samples from the beginning and ends of the 20th century (107 male, 53 female). Statistically significant differences between them was found. Finally, we proposed regression equations for calculating the stature of the contemporary Czech population usable in forensic practice.

A phylogeographic analysis of haplogroup D5 and its implications for the peopling of East Asia.M.C. DulikWhile genetic studies have focused on the Altai region of South Siberia as a possible place of origin for Native Americans, it is also possible that it played a similarly significant role in the peopling of East Asia. A Siberian connection to other East Asian populations has already been proposed based on archaeological, linguistic and classical genetic marker evidence. In this study, we examined a rare and ancient haplogroup, D5c, in an effort to elucidate early population movements in East Asia. Previous studies suggested that D5 first emerged in China andspread northwards from there. However,given the number of D5c individuals (12) and the range of variation in D5 from the Altai region, it is conceivable that this haplogroup instead originated in South Siberia and spread from there during the initial movements of Paleolithic peoples. To est this hypothesis, we obtained complete mtDNA sequences for individuals represented by aplogroups D4 and D5 and acquired additional sequences available through GenBank and published literature. We then analyzed the entire dataset with the reduced median network approach andphylogeographic modeling. Our results suggest that Southern Siberia did play acritical role in the spread of the D5 haplogroup. This focus on relatively uniquemtDNA lineages specific to certain populations allowed us to better understandthe processes of ancient settlement and subsequent population movements that helped shape the current genetic landscape of East Asia.

More than meets the eye: LB1, the transforming hominin.R.B. Eckhard et al.

LB1 is not a microcephalic.D. Falk1 et al.

Is there biological meaning to “Hispanic” in New Mexico?H.J.H. Edgar, C.M. Willermet

Establishing the nature of the differences between skull samples from two populations.S.P. Evans et al.A sample of 1188 skulls from the Romano-British site at Poundbury shows differences from the 18th century sample of 822 skulls from Spitalfields. Both sites are in the south of England, but 1400 years apart in time. The differences between the sites could be due to immigrations over time and/or to adaptation to the environment. The aim of the study was to establish the nature of the differences, in particular the relative importance of genetic and acquired traits.Frequencies of 22 selected non-metric traits in juvenile, female and male skulls were analysed. Initial logistic regression analyses established that there was a substantial difference between the two sites and between juveniles and adults, with some sexual dimorphism. The modified meanmeasure of divergence, used to calculate overall distances between the groups, showed the juvenile groups to be closer to each other than to adults from their respective sites. Across sites, males were most distant from each other. The largest distance was between Spitalfields juveniles and males. Principal coordinate analysis, followed by a jackknife stability analysis, revealed a pattern indicating that this came about through growth and adaptation. Omitting traits in turn, procrustes methods were used to identify the most influential, all of whichwere acquired through ageing or lifestyle. Without these traits there was no significantdifference between the two juvenile groups and no sexual dimorphism. These results show the importance of the behavioural environment in determining morphology, and the resilience of populations to genetic change.

Peopling of the Pacific: resolving the controversy.J.S. Friedlaender et al."Our survey of mitochondrial DNA, Ychromosome, and over 600 short tandem repeat polymorphisms and 200 insertiondeletions from over 40 Pacific populations indicates Polynesians have their geneticorigins to both Melanesian and Taiwanese (Southeast Asian) populations in significant degrees. In Island Melanesia, there is a small but clear ancient genetic footprint in certain Oceanic-speaking populations (i.e., linguistically related to Polynesian). The survey results underscore the extraordinary diversity of Island Melanesian populations from one language group to another, and from island to island. This is the result of the small sizes of the populations and the very long extent of modern human settlement there (over 30,000 years)."

Demographic simulations of the admixture between foragers and farmers in central European Neolithic.P. Galeta, J. Bruzek.

William White Howells: A physical anthropologist in the making.E. Giles

The relationship of Nubians with their neighbors, the Egyptians.By, K. Godde.

The Phylogeography of Haplogroup N1aGokcumen O et al.Recent studies have revealed a complex geographic distribution of haplogroup N1a. This rare and distinctive lineage is widely distributed across Eurasia and Africa, but always found at very low frequencies. However, despite its rarity, the genetic diversity within N1a has remained relatively high (h=0.9605). The reduced median network of N1a haplotypes not only reflectsthis level of diversity, but also exhibits several relatively well-defined branches. Thedistribution of N1a is intriguing because of revealing previously unrecognized connections between populations. What makes N1a even more interesting is the prevalence of this lineage in ancient European populations. Haak et al. (2005) found that 25% of their European Neolithicsamples belonged to N1a and dated to ~5000 BCE, whereas the frequency of this lineage in contemporary Europeans is only ~0.2%. In addition, an Iron Age skeleton from Kazakhstan had an N1a haplotype, suggesting the existence of this lineage in the Altai Republic in ~500BCE (Ricaut et al. 2004). Indeed, we found several haplogroup N1a mtDNAs in indigenous Altaians and Altaian Kazakhs. To further elucidate the phylogeography of this lineage in Central Asia, we sequenced the whole mtDNA genomes of our N1a haplotypes, and analyzed the resulting data with several quantitative methods and simulation programs to estimate their expansion times and spatialdistribution in Eurasia. Our findings suggest that there are two well-defined sublineageswithin N1a, and that the dispersal of this haplogroup could be associated with the Neolithic expansion and with prehistoric interactions between Central Asian and European populations.

Understanding human races: the retreat of neutralism.Henry HarpendingDiscussion and debate about human races has been dominated for decades by neutral theory and statistics. Since this literature never posed a real question, it has never produced an answer. Lewontin's 1972 paper with its claim that a value of 1/8 of a statistic like Fst is “small” and that this means that human race differences are insignificant is a staple of our textbooks. Recently geneticists have had a closer look and pointed out that Fst of 1/8 describes differences among sets of half sibs and few claim that half sibs are insignificantly related. Anthony Edwards has shown that the significance of differences is in the correlation structure of a large number of traits, again denying the Lewontin assertion that human differences are small. Alan Templeton in 1998 claimed that human races were less differentiated that races of some other large mammals, but he compared human nuclear DNA statistics with statistics from mtDNA in the other species. An appropriate comparison shows that human are more, not less, differentiated than other large mammal species. Since neutral differences are a passiverecord of demographic history they are not very significant for issues of functional biology. Newly available data sources allow us to study the natural selection of race differences instead of their drift. It appears that there is a lot of ongoing evolution in our species and the loci under strong selection on different continents only partially overlap. Human race differences may be increasing rapidly.

Acceleration of adaptive evolution in modern humans.J. Hawks and G. CochranHumans vastly increased in numbers during the past 40,000 years. Recent surveys of human genomic variation have suggested a large surplus of recent positive selection, indicated by excess linkage disequilibrium and skewed SNP frequency spectra. We applied estimates of prehistoric and historic population sizes to estimate the importance of population growth in explaining the number of recent adaptive mutations. Our estimates are consistent with genomic evidence in suggesting that the rate of generation of positively selected genes has increased as much as a hundredfold during the past 40,000 years.

Do skeletal features reflect this genomic evidence of selection? Under positiveselection, rapid appearance of new variants during the terminal Pleistocene and earlyHolocene would cause maximal phenotypic change during the last 2000-4000 years. We compared original and published series of Holocene cranial data from Europe, Jordan, Nubia, South Africa, and China, in addition to Late Pleistocene samples from Europe and West Asia, to test the hypothesis that the genomic acceleration in positive selection correlates with phenotypic evolution during this time period. A constellation of features in the face and cranial vault, notably including endocranial volume, changed globally during this time period and documents common patterns of selection in different regions. Holocene changes were similar in pattern and chronologically faster than those at the archaic-modern transition, which themselves were rapid compared to earlier hominid evolution. In genomic and craniometric terms, the origin of modern humans was a minor event compared to more recent evolutionary changes.

Patterns of admixture in Mexican Americans assessed from 101,150 SNPs.M.G. Hayes et al."No significant differences were observed between the 10 subsets, allowing us to average the admixture estimates across the subsets: 68% European, 27% Asian (as a proxy for Native American), and 6% African."

Secular trends of the European male facial skull from the Migration Period to the present.E. Jonke et al.We examined secular trends in the facial skull over three Central European samples spanning more than 13 centuries. Data are 43 conventional cephalometric landmark points for samples dating from 680–830 CE, from the mid-19th Century, and from living Austrian young adult males. Methods of geometric morphometrics demonstrate shape differences across the samples, and alsodifferences in allometry. There is a stronginteraction between these, so that group mean differences are different for small and large individuals (equivalently, allometry isdifferent from period to period). The oldest sample, from the Migration Period, exhibitsallometric features that may possibly be Turkic. There are implications for thecraniofacial biologist interested in growth trends or growth predictions in ethnicallymixed populations. There are also implications for the discussion concerning the morphology of the Avars (an ethnic group of probably Central Asian origin who conquered large parts of Central Europe during the Migration Period and who interbred with other incoming groups after their conquest by Charlemagne), and also the relation of these findings to current thinking on gnathic reduction trends.

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